A solution of Fe2(SO4)3 is electrolyzed for ‘x’ min with a current of 1.5 A to deposit 0.3482 g of Fe. The value of x is _______. [nearest integer]
Given : 1 F = 96500 C mol–1.
Atomic mass of Fe = 56 g mol–1
Fe3+ + 3e– → Fe
Moles of Fe deposited
\(=\frac{0.3482}{56}=6.2×10^{-3}\)
For 1 mole Fe, charge required is 3 F
For 6.2 × 10–3 mole Fe, charge required is
3 × 6.2 × 10–3 F
Since, charge required = 18.6 × 10–3 × 96500 C
= 1794.9 C
And,
1.5 × t = 1794.9
\(t=\frac{1794.9}{1.5×60}\) min
t ≃20 min
(i) State Henry’s Law. Give two applications of it.
(ii) Draw the vapour pressure-mole fraction curve for a non-ideal solution having positive deviation, if A and B are the two volatile components.
A substance 'X' (1.5 g) dissolved in 150 g of a solvent 'Y' (molar mass = 300 g mol$^{-1}$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent 'Y' is $____________ \(\times 10^{-2}\). (nearest integer)
[Given : $K_{b}$ of the solvent = 5.0 K kg mol$^{-1}$]
Assume the solution to be dilute and no association or dissociation of X takes place in solution.
Inductance of a coil with \(10^4\) turns is \(10\,\text{mH}\) and it is connected to a DC source of \(10\,\text{V}\) with internal resistance \(10\,\Omega\). The energy density in the inductor when the current reaches \( \left(\frac{1}{e}\right) \) of its maximum value is \[ \alpha \pi \times \frac{1}{e^2}\ \text{J m}^{-3}. \] The value of \( \alpha \) is _________.
\[ (\mu_0 = 4\pi \times 10^{-7}\ \text{TmA}^{-1}) \]